Step 1: Divide the number into separate digits:
8496 => 8 4 9 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 4 = 4
4 to 9 = 5
9 to 6 = 3
6 to 8 = 2
Step 3: Combine the filters to a string:
4 5 3 2 = 4532